In the present days, many researchers pay attention to location estimation methods because of incresing of location based services. Wireless LAN based location estimation is attractive to estimate indoor location of mobile devices because GPS that is used mainly to estimate locations cannot be used indoors. The finger print method is one of the most promising method and association rules were introduced to improve the performance. In this study, a center of gravity is applied to enhance the accuracy of estimated location. A series of simulation based experiments was carried out to compare its performation with the one of the existing method.